This invention relates to a process for converting oligomerizable olefins, e.g., C.sub.2 -C.sub.16 olefins, to higher molecular weight hydrocarbon products including those boiling in the gasoline, distillate, and lube range over catalyst comprising synthetic porous crystalline MCM-49. The present process provides high conversion, especially for conversion of lower olefins such as propylene, to valuable products useful, as examples, for etherification and as high octane gasoline.
Zeolitic materials, both natural and synthetic, have been demonstrated in the past to have catalytic properties for various types of hydrocarbon conversion. Certain zeolitic materials are ordered, porous crystalline aluminosilicates having a definite crystalline structure as determined by X-ray diffraction, within which there are a large number of smaller cavities which may be interconnected by a number of still smaller channels or pores. These cavities and pores are uniform in size within a specific zeolitic material. Since the dimensions of these pores are such as to accept for adsorption molecules of certain dimensions while rejecting those of larger dimensions, these materials have come to be known as "molecular sieves" and are utilized in a variety of ways to take advantage of these properties. Such molecular sieves, both natural and synthetic, include a wide variety of positive ion-containing crystalline silicates. These silicates can be described as a rigid three-dimensional framework of SiO.sub.4 and Periodic Table Group IIIA element oxide, e.g., AlO.sub. 4, in which the tetrahedra are cross-linked by the sharing of oxygen atoms whereby the ratio of the total Group IIIA element, e.g., aluminum, and silicon atoms to oxygen atoms is 1:2. The electrovalence of the tetrahedra containing the Group IIIB element, e.g., aluminum, is balanced by the inclusion in the crystal of a cation, e.g., an alkali metal or an alkaline earth metal cation. This can be expressed wherein the ratio of the Group IIIB element, e.g., aluminum, to the number of various cations, such as Ca/2, Sr/2, Na, K or Li, is equal to unity. One type of cation may be exchanged either entirely or partially with another type of cation utilizing ion exchange techniques in a conventional manner. By means of such cation exchange, it has been possible to vary the properties of a given silicate by suitable selection of the cation. The spaces between the tetrahedra are occupied by molecules of water prior to dehydration.
Prior art techniques have resulted in the formation of a great variety of synthetic zeolites. Many of these zeolites have come to be designated by letter or other convenient symbols, as illustrated by zeolite Z (U.S. Pat. No. 2,882,243); zeolite X (U.S. Pat. No. 2,882,244); zeolite Y (U.S. Pat. No. 3,130,007); zeolite ZK-5 (U.S. Pat. No. 3,247,195);zeolite ZK-4 (U.S. Pat. No. 3,314,752); zeolite ZSM-5 (U.S. Pat. No. 3,702,886); zeolite ZSM-11 (U.S. Pat. No. 3,709,979); zeolite ZSM-12 (U.S. Pat. No. 3,832,449); zeolite ZSM-20 (U.S. Pat. No. 3,972,983); zeolite ZSM-35 (U.S. Pat. No. 4,016,245); and zeolite ZSM-23 (U.S. Pat. No. 4,076,842), merely to name a few.
The SiO.sub.2 /Al.sub.2 O.sub.3 ratio of a given zeolite is often variable. For example, zeolite X can be synthesized with SiO.sub.2 /Al.sub.2 O.sub.3 ratios of from 2 to 3; zeolite Y, from 3 to about 6. In some zeolites, the upper limit of the SiO.sub.2 /Al.sub.2 O.sub.3 ratio is unbounded. ZSM-5 is one such example wherein the SiO.sub.2 /Al.sub.2 O.sub.3 ratio is at least 5 and up to the limits of present analytical measurement techniques. U.S. Pat. No. 3,941,871 (Re. 29,948) discloses a porous crystalline silicate made from a reaction mixture containing no deliberately added alumina in the recipe and exhibiting the X-ray diffraction pattern characteristic of ZSM-5. U.S. Pat. Nos. 4,061,724, 4,073,865 and 4,104,294 describe crystalline silicates of varying alumina and metal content.
U.S. Pat. No. 4,439,409 refers to a composition of matter named PSH-3 and its synthesis from a reaction mixture containing hexamethyleneimine, an organic compound which acts as directing agent for synthesis of the presently used MCM-49. A composition of matter appearing to be identical to the PSH-3 of U.S. Pat. 4,439,409, but with additional structural components, is taught in European Patent Application 293,032. Hexamethyleneimine is also used for synthesis of MCM-22 in U.S. Pat. No. 4,954,325; MCM-35 in U.S. Pat. 4,981,663; and a ZSM-12 material in U.S. Pat. 5,021,141. A composition of matter referred to as zeolite SSZ-25 is taught in U.S. Pat. No. 4,826,667 and European Patent Application 231,860, said zeolite being synthesized from a reaction mixture containing an adamantane quaternary ammonium ion.
Developments in zeolite catalysts and hydrocarbon conversion processes have created interest in utilizing olefinic feedstocks, such as petroleum refinery streams rich in lower olefins, for the production of C.sub.5 + gasoline, diesel fuel, lube stocks, etc.
U.S. Pat. No. 4,956,514 discloses conversion of light olefins to heavier hydrocarbons, e.g., gasoline, distillate, and lube boiling range products, over catalyst comprising MCM-22, a crystalline material taught in U.S. Pat. No. 4,954,325.
U.S. Pat. Nos. 3,960,978; 4,021,502; 4,150,062; 4,211,640; 4,227,992; 4,456,779; and 4,547,612 disclose the conversion of C.sub.2 -C.sub.5 olefins, alone or in admixture with paraffinic component(s), into higher hydrocarbons over zeolites having controlled acidity.
U.S. Pat. No. 4,524,232 discloses a combination process for producing high viscosity index lubes from light olefins employing in separate stages a particular pore size zeolite catalyst, e.g., ZSM-23, and another pore size zeolite catalyst, e.g., ZSM-5.